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Numerical simulation of pressure distribution in bristle seal for turbomachinery |
KANG Yuchi 1,2, LIU Meihong1*, WANG Xueliang1, TAN Yongfa1, LIU Jinbin1 |
1.Mechanical and Electrical Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650504, China; 2.Department of Mechanical Engineering, Blekinge Institute of Technology, Karlskrona, Blekinge 37179, Sweden |
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Abstract In order to further study the pressure distribution in bristle seals, a uniformed two-dimensional closed staggered tube bundle model representing a bristle pack cross-section was proposed and the fluid flow through the bundle was solved by computational fluid dynamics(CFD)method. Accor-ding to the critical Reynolds number for boundary layer transition, a new method was proposed to decide the fluid flow regime in the bundle. The pressure and velocity distributions in the bundle were studied under various pressure differentials across the seal. The influences of distance between bristles and number of circumferential bristle rows on the pressure distribution were tackled. It is shown that the pressure distributions in the uniformed two-dimensional closed staggered tube bundle model agrees well with the previous experimental data. The pressure distributions are like “V”, while the velocity distributions are like the inverted “V”. The pressure borne by the rear 1/3 part of the bristle pack is higher than that by the front 2/3 part. Moreover, the percentage of the pressure differential borne by the last 5 bristle rows increases with increasing total pressure differential. The pressure differential borne by the last bristle row is higher than that by a few rows in front of it. A reduced distance between bristles can allow the pressure to be distributed more even from one row to another. Bristles equally spaced can ensure an even pressure distribution rather well. Increasing the number of rows can also have the same effect.
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Received: 09 September 2016
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